1. Field of the Invention
The present invention relates to a communication switching system including at least a multiplexer to first and second input terminals of which a first input cell stream and a second input cell stream are applied respectively, said first and second cell streams comprising first and second cells occupying predetermined and arbitrary time slots of respective first and second time frames having a first and a second time slot frequency respectively, and which provides at its output terminal an output cell stream wherein said first and second cells occupy predetermined and arbitrary time slots of a third time frame having a third time slot frequency, each of said cells comprising data.
2. Description of the Prior Art
Such a communication switching system is described in the German patent application No. P3742939.6 (H. Weik 1) filed on Dec. 18, 1987. Therein the multiplexer inserts the second or ATM (Asynchronous Transfer Mode) cells of the second input cell stream in free time slots of the first input cell stream comprising first or STM (Synchronous Transfer Mode) cells the resultant cell stream being the output cell stream. This means that the known multiplexer is specially adapted to be used in a hybrid STM/ATM communication witching system and not in a purely ATM communication switching system. Eventual evolution towards the latter would thus necessitate another type of multiplexer.